US2281174A - Material sizing mechanism - Google Patents

Description

April 2.8, 1.942,1 .l w. STELE 2,2s1,\174

MATERIAL S IZ ING MECHANISM Filed March 7, 1939 2 Shleets-Sheet 2 Z/INVENTOR m 4996 .7 f

TTORNEYS i Patented Apr. 28, 1942 UNITED STATES PATENT OFFICE 2 Claims.

The 'invention .relates to novel and useful ."mechanism for separating or grading comminuted or particulate materials according to size.

Objects and advantages of the invention will be set forth in part hereinafter and in part will be obvious herefrom, or may be learned by practice with the invention, the same being realized and attained by means of the instrumentalities and combinations pointed out in the appended D-claims.

The invention consists in the novel parts, con- :struction, arrangements, combinations and imjprovements herein shown and described.

The accompanying drawings, referred to herefin and constituting a part hereof, illustrate one :embodiment of the invention, and together With the description, serve to explain the principles f-of the invention.

Of the drawings:

Fig. 1 is a perspective of the mechanism embodying the invention, viewed from the discharge side;

Fig. 2 is a top plan view of the sizing deck;

Fig. 3 is a transverse vertical section on line 3-3 of Fig. 2;

Fig. 4 is a transverse vertical section on line 4-4 of Fig. 2;

Fig. 5 is an enlarged detail in perspective of a portion of the deck surface; and

Figs. 6, 7, 8 and 9 are successive vertical sections taken on the respective section lines indicated in Fig. 4, and illustrating the successive sizing actions of the deck surface.

In separating intermixed comminuted materials of various sizes into several size ranges or grades, the invention employs the principle whereby, under the influence of gravity and agitation or shaking motion, the smallest particle of a group will tend tov filter or settle to the lowermost stratum while the larger particles will arrange themselves approximately in order of size upwardly. The invention further employs the principle whereby, in a group of diiferently sized particles, those having the greatest diameter will tend to travel or roll most rapidly over a surface, while the smallest will tend to cling and move most sluggishly over the same surface under the same motivating force.

One object of the invention is to provide a rugged and inexpensive mechanism for sizing particulate materials in accordance with the foregoing principles. The invention provides a sizing mechanism embodying a deck or .sizing surface lyng in substantially a single continuous plane and having a relatively simple, consistent 7 manufacture of fibre board and the like.

sizing surface which is adapted to perform a very rapid, progressive and very efiicient sizing or grading action. Theiconstruction of the deck is such that it is readily adapted for use in multiple forms so that several relatively light but rugged decks may be mounted in superposed or nested relation on a single actuating frame, thereby to multiply the capacity of the actuating mechanism.

The invention has been found exceedingly useful in the size grading of materials which are too light in weight and/or small in size to 'be size graded by ordinary screening methods' The I invention also is highly effective in the sizing and separating of materials containing fibrous particles different in size and/or shape from the other particles forming the mass.

As an example of shape Variations, cockle may p be separated from Wheat where the grains are of the same Weight and of the same diameter on the smaller axis. One material which the invention handles very eifectively is ground hemp, which is a particulate material used in the This material is so light that it cannot be screened and is so highly fibrous that the particles clog an ordinary screen. Also, said material cannot be successfully separated or size-graded by a pneumatic aspirator, but the present invention very successfully makes a nice size gradation into a relatively large number of clearly defined size grades. The invention has also been found effective in the -grading and separation of fibrous material from cereal mill products, such as the separation of bran hulls or particles from flour or meal. The invention is also adapted to perform very efficient sizing with comminuted mineral materials,^such as ores, coal and the like, it being understood that the operation is primarily adapted to the sizing of materials of substantially uniform specific gravity, but is not confined to such materials. i

It will be understood that the foregoing general description and the following detailed description as Well, are exemplary and explanatory of the invention but are not restrictive thereof.

Referring now in detail to the present preferred embodiment of the invention illustrated by way of example in the accompanying drawings, the invention comprises a sizing deck or 'surface l mounted to reciprocate longitudnally in a conventional manner. As shown, the surface I is formed on a rigid frame comprising the backing plate 2 which is supported upon suitable frame members 3 and along its rear or left hand end is provided with a vertical frame member and material retaining wall 4.

The deck and supporting frames are mounted for reciprocation by a pitman 6 which is pivotally connected to the end wall 4 by a conventional bracket l. The pitman is given a reciprocating movement, preferably of the type common in separating and grading tables, i. e., an upward and forward stroke followed by a relatively short and rapid falling return stroke. As emboclied, said reciprocation is imparted to the pitman by a suitable eccentric crank 8 mounted on the actuatng shaft 9, to Which rotary movement may be imparted by any suitable power means connected to the drive pulley IG. The shaft 9 and its bearings are suitably supported in A-shaped frames ll, mounted on rigid horizontal members H2. A leaf spring |4 may be provided to bear against the bracket 'I and thus partially damp the stroke. The lower ends of the springs M are curved upwardly about separate pintles on the bracket 'l to support the bracket and the left hand end of the deck frame. The opposite or forward portion of the deck is suitably supported for rocking movement with respect to the horizontal frame i2, as by links, not shown, pivotally connected with the axle H which is suitably journalled in the vertical frames l. As shown, the deck is preferably mounted at a considerable inclination transverse to the reciprocatory stroke of the pitman 6 so that material will have a gravital fiow from the feed end 2D of the deck toward the discharge or delivery edge 2i. The deck also preferably has a somewhat less longitudinal slope upwardly from the drive end or wall ill toward the opposite end. Any suitable means, not shown, may be provided for varying the longitudinal and/or transverse slopes of the deck as required in practice.

As indicated, the deck is designed and mounted so that the material to be sized is fed on at the narrow feed end 2G, by a suitable feed hopper or the like, not shown. The deck widens progressively from the feed end 29 toward the discharge edge 2l, the end or side opposite the straight retaining wall 4 being preferably inclined to give the deck essentially the shape of a right triangle, although other forms may be used. A retaining and guiding wall or rail 22 may be provided along the diagonal edge of the deck to prevent spillage. of material overr said edge.

Referring now to the surface construction of the deck l, same is designed to cause the unsized materials to spread thereover .in a relatively thin sheet and to undergo the progressive sizing action eiected by the influence of gravity and the agitating and impelling effects of the reciprocaton. As previously described, the surface of the deck is provided with a plurality of parallel grooves 25 which act to catch the materials as they travel across the deck and to guide them generally in the direction of reciprocation While graduallyreleasing the larger size particles to roll by gravity across the deck towards the discharge edge. As embodied, the deck surface is preferably formed as an integral unit into which the grooves 25 are cut or molded. A grooved molding of rubber has been found highly effective in operation, as the rubber surface is somewhat frictional, thus tending to retain the finer particlesand prevent too rapid movement of the materials along the grooves. I-Iowever, other substances are alsosuitable and preferable with some materials. A deck of molded plastic such as Bakelite is effective and with some materials a deck formed of wood or metal may be found desirable.

In accordance vvith the invention, the grooves 25 are preferably V-shaped and taper in depth and in width from the rear or left-hand side 4 of the deck towards the inclined or terminal side 22. As shown in Fig. 5, in the preferred construction the grooved deck surface is formed of an integral slab or molding 26 in which the grooves are cut to a uniform distance from the bottom of the slab, the areas 21 between the grooves being planed down to form increasingly widening surfaces so that the grooved portions themselves become increasingly shallow and narrow while retaining essentially the same side slopes. In another form, however, the grooves may be formed with the bottoms sloping upwardly away from the bottom of the slab 26 so that the over-all thickness of the slab will be uniform throughout. It will be understood that the widest and deepest portion of the grooves lies along the rear Wall ll of the deck, the grooves preferably being formed of substantially equal width along the line shown in Fig. 3, so that the grooves widen to the left of said line and narrow to the right in Fig. 2. Thus the widest and deepest groove will be found along the wall ll near the lower left-hand corner of the deck.

As shown in Figs. 1 and 2, the grooves 25 are preferably disposed at a slight angle to the direction of the reciprocatng impulse, said grooves extending forwardly and upwardly, that is, toward the terminal edge 22 and away from the spillage edge 2l. Thus the grooves 2'5 direct the material in the general direction of the reciprocation but preferably somewhat upwardly and transversely thereof. In some cases, the grooves 25 may be extended parallel to the line of reciprocation, i. e., parallel to the spillage edge 2l, and somewhat the same action on the material accomplished by increasing the longitudinal slope of the deck, although the preferred construction is that as shown. In any case, the grooves terminate short of the terminal edge 22 to merge with and form a Smooth ungrooved surface or passage 28 along the deck parallel to the wall 22, as shown in Figs. 1 and 2.

It will be clear that all of the material will be 'delivered in various sizes or size gradatons along the spillage edge 2,! of the deck. Suitable means for maintaining the size separation of the several grades and delivering same to separate receptacles comprises a spillage plate or apron 30 fixed below the deck plate 2 and extending parallel to the edge 2I. A plurality of material-dividing or cutting fingers Si are mounted on the apron 30 and may be positioned at various places angularly and rectilinearly therealong so as to accommodate the delivery operation to the grading action of the deck. As shown, the fingers 3l are individually tightly gripped in any desired location along the plate 30 by spring-gripping means 32.

Referring now to the operation of the hereinbefore described mechanism, same will be illustrated in connection with Figs. 6 to 9 in which a number of particles P of varying sizes are shown for purposes of explanation and illustration. While these particles are shown as generally spherical, such showing is purely illustrative-and diagrammatic as it will be understood that the invention is adapted and designed to size and grade particles of rwidely different shapes as well as size, being particularly efficacious for the separation of partcles of fibrous nature having intermixed elongated slivers and the like such as occur in ground hemp for example.

The material is fed on along the feed edge 20 and preferably near the left-hand corner thereof and the feed is regulated to maintain a relatively thin sheet of the material fiowing over the deck surface. The grooves 25 act to catch and retain pockets of the materials and to hold them While they undergo the sizing effects of gravity and the agitation of the reciprocating impulses. It will be understood that the deck surface is impervious throughout, so that no upward currents of air or other disturbing forces may act on the materials. As indicated in Fig. 6, the materials in the grooves rapidly tend to distribute themselves vertically according to size in a known manner. That is, the finest partcles filter to the bottom of the groove while the largest ones are displaced and work upwardly to the surface, the intermediate size partcles arranging themselves downwardly in order of decreasing size as shown. The reciprocatory impulses tend to move the vertically sized materials in the groove therealong toward the terminal edge 22. As the groove begins to diminish in width and depth, the uppermost and largest partcles will quickly work over the edges 21 and roll transversely toward the spillage edge 2l. This causes the largest partcles to travel progressively toward the spillage edge 2| at a fairly rapid rate, so that ultimately all the largest sized p partcles will be delivered adjacent the left hand end of the spillage edge. The smallest partcles tend to cling to the bottoms of the grooves and to travel slowly therealong so that ultimately the finest partcles reach the ends of the grooves and are delivered into the smooth passageway 28 along which they may travel without interruption downwardly and toward the right to discharge. The action along each groove is progressive and continuous so that the partcles of intermediate size tend to distribute themselves according to size from the largest at the left-hand end of the spillage edge 2| to the finest at the right-hand end. Any coarser partcles which improperly may arrive in the passageway 28, especially near the upper or initial part thereof, will tend to roll U downwardly by gravity and soon fall into a lower groove 25 where they will be resubjected to the sizing action.

By disposing the grooves 25 at a slight angle across the direction of the impulse, as shown, I

have found that the efficiency of the sizing action is considerably enhanced. The larger partcles thus tend to emerge and cross the ridges 27, being impelled at an angle thereto, whereas with grooves parallel to the impulse the partcles tend to follow the grooves even though stratified near the top thereof. Accordingly, by the use of the inclined grooves, I am able to size materials very rapidly and to make a very sharp and efficient segregation of sizes.

The invention in its broader aspects is not limited to the specific mechanisms shown and described but departures may be made therefrom within the scope of the accompanying claims without departing from the principles of the invention and without sacrificing its chief advantages.

What I claim is:

1. A mechanism for sizing comminuted unsized material including in combination an inclined impermeable support, lying in a substantially continuous plane, means for feeding material to travel by gravity over the support, means for reciprocating the support to propel material thereon across the direction of its flow by gravity, a plurality of material-collecting and settling impervous grooves substantially V- shaped in cross section for vertically sizing the material therein and for guiding propelled material over the support and across the direction of its gravital flow, said grooves being continuous from end to end and of dimirn'shing depth and width longitudinally in the direction of travel of the material propelled therealong.

2. A mechanism for sizing comminuted unsized material including in combination a transversely inclined impermeable support formed of frictional material and lying in a substantially contiuous plane, means for feeding material to travel by gravity over the support, means for reciprocating the support to propel material thereon across the direction of its flow by gravity, a plurality of impervious material-collecting and settling grooves substantially V-shaped in cross section for vertically sizing the material therein and for guiding propelled material over the support and across the direction of its gravital flow, said grooves being continuous from end to end and of diminishing depth and width longitudinally in the direction of travel of the material propelled therealong, said support also being inclined upwardly in the direction of propulsion, the grooves extending toward the feed end at a relatively slight angle to the direction of propulsion.

OLIVER W. STEELE.

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